GORAKHPUR, May 15 -- Officials are intensifying efforts to trace the source of the avian influenza virus detected at the Gorakhpur zoo. Four dead crows were found at different locations within the zoo during the first week of May. Zoo director Dr Vikas Yadav stated that migratory birds are known carriers of avian influenza and crows are particularly susceptible to the virus. An animal husbandry department team conducted an inspection of the zoo on Wednesday and is expected to submit its findings to senior officials by Friday. Zoo's deputy director Dr Yogesh Pratap Singh confirmed that the tigress, which died on May 7 and tested positive for the avian influenza virus, was never served chicken. He added the chances of the virus being present in buffalo meat are considered minimal. Dr Singh also said the occurrence of dead crows was neither frequent nor in large numbers, hence it did not initially raise an alarm. Gorakhpur's chief veterinary officer Dr Dharmendra Pandey said samples from 105 birds across 248 poultry farms have been collected and will be sent to Indian Veterinary Research Institute (IVRI), Bareilly....